In the early days of virology research, since human virions were not observed under the microscope at the time, and the virus could not be artificially cultured, the isolation of the virus was very important for clarifying the biological characteristics of the virus. In the case of fashion-free high-speed centrifuges, attempts have been made to separate viruses from diseased tissues using horsepower centrifuges. Until the advent of high-speed and ultracentrifuges, it is possible to isolate and prepare viruses based on virologicality. Today, the isolation of viruses, in technical terms, the purification of viruses, remains a critical step in the molecular biology of virology.
In 1953, Stanley extracted and crystallized TMV for the first time, an important milestone in the history of virology. Later, people have separated the virus from different organizations. Purification of the virus is the process of distinguishing the virions from the host with the host cell components. The principle is to use the characteristics of the protein and macromolecular granules of the virus, and the difference in physicochemical properties of the host cell components to distinguish the virions and maintain the invasiveness as much as possible. The purpose of purifying the virus is to study the physicochemical, biological characteristics, chemical composition, composition, proliferation process and mechanism of the virus, and to prepare high titer antiserum. Taking plant viruses as an example, humans first purify viruses that are high in the plant and stable in vitro, such as TMV and potato X virus. At present, more and more technologies and procedures can be used to purify viruses with different concentrations and stability, which lays a foundation for the research work of the virus.
Electron microscopy has always been an indispensable tool for studying viruses. After 1960, samples were negatively stained with heavy metal salt solutions, and the structure of the virus was studied in detail, which greatly advanced the understanding of the virus. Electron microscopy is an important diagnostic tool for viruses that cannot grow in cell culture.
Cell culture has greatly promoted the study of virology. It was first used in the culture of poliovirus, and has since been widely used in the isolation and culture of various viruses in human medicine and veterinary medicine. Dulbecco (1952) invented the plaque technique to enable quantitative detection and cloning of viruses.
The development of biochemistry and molecular biology provides a powerful weapon for the study of virology. For example, X-ray crystal diffraction, protochromia and nuclear magnetic resonance techniques are used to study the three-dimensional structure of viruses; polyacrylamide gel electrophoresis (PAGE) is used for the analysis of viral nucleic acids and polypeptide components. The use of biochemical technology to identify viral nucleic acid polymerases, especially anti-recording enzymes, is not only theoretically but also practically significant. Nucleic acid hybridization technology provides a sensitive and reliable means for virus identification and diagnosis. DNA recombination technology and synthetic peptides have opened up new avenues for the development of new vaccines. At present, immunofluorescence technology is an important means to study the process of virus infection, localization and viral gene function.
Chinese scholars have contributed to the development of virology. Tang Feifan studied herpesvirus in the United States in 1925. He and his mentor Zinsser used physics to study the nature of the virus, proving that the virus is a self-replicating particle present in the host cell, which has made important importance for the establishment of virology. contribution.
Since the virus is the smallest organism in the microorganism, it is not observed under ordinary microscopes. To detect the presence of a virus in the early 20th century, it must be judged by injecting an infection and observing the morbidity or mortality of the animal. Obviously this detection method is very primitive. Since the virus does not have its own enzyme system, it can survive on the microbial culture medium by parasitic living cells, which makes it difficult to find new techniques for cultivating viruses. However, virus culture is the most basic and crucial step in virus research. It can be said that without the establishment of new technology for virus culture, there is no breakthrough and development of virus research. Many countries have invested a lot of manpower and material resources for this. Many well-known scholars in the world have been pondering for decades. In 1943, Huang Yuxiang published a paper in the United States that had a major impact on virology research. " Further studies on the titration and neutralization of Western equine encephalitis virus in tissue culture." The results of this research made the virus in the test tube become a reality, and thus got rid of the original backward method of artificial propagation of the virus by animal and chicken embryo culture. This new technology can be summarized as follows: In the first step, the animal tissue is processed and digested into monolayer cells, and a certain nutrient is given to survive in the test tube; in the second step, the virus is inoculated into the cells. After a period of time, the cells will have a series of pathological changes. Observers can observe and judge the presence or absence of virus propagation by observing the presence or absence of pathological changes in the cells with an ordinary microscope. This new technology raises the virus from the animal level of experimental animals and chicken embryos. Increase the level of cells to in vitro tissue culture.
It is this new technology that broadens the thinking of virological scholars internationally. Many virologists have used or improved this technique to successfully discover the pathogens of many viral diseases and isolate many new viruses, solving the viral causes of some of the lesser known diseases at the time. Some scholars have also used tissue culture techniques to prepare vaccines, which have achieved active immunization of the population and contributed to the control and elimination of viral diseases. In the 1950s, the famous American virologist Enders won the Nobel Prize, which was based on the technology of Huang Yixiang. The "World Who's Who" published in the United States in 1982-1985 called this technology a foundation for modern virology. This technique has been used in many countries around the world to isolate epidemic hemorrhagic fever, measles and polio. In recent years, the globally causing vibration of HIV has also been isolated using tissue culture technology.
Zhu Xianming discovered in the United Kingdom in 1948 that the same virus can be morphologically different, and the first time the influenza virus is cleaved into biologically active subunits. Based on this, the structural model of the virus is proposed. This hypothesis is later clarified. Various viral structures have pioneered and prepared the basis for the theory and method for studying subunit vaccines. Zhu Xianming also found β-statin, which inhibits hemagglutination of influenza virus in normal serum. In 1943, Gao Shangyin observed that the virus infects different hosts and maintains stable physicochemical and serological characteristics in the study of tobacco mosaic virus. It has a certain status in the history of virology.
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